New compounds for the treatment of neurological, psychiatric or pain disorders

ABSTRACT

The present invention is directed to novel compounds, their use in therapy and pharmaceutical compositions comprising said novel compounds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/523,717, filed Sep. 20, 2006, which claims priority to U.S.Provisional Application No. 60/721,527, filed Sep. 29, 2005, both ofwhich are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention is directed to novel compounds, their use intherapy and pharmaceutical compositions comprising said novel compounds.

BACKGROUND OF THE INVENTION

Glutamate is the major excitatory neurotransmitter in the mammaliancentral nervous system (CNS). Glutamate produces its effects on centralneurons by binding to and thereby activating cell surface receptors.These receptors have been divided into two major classes, the ionotropicand metabotropic glutamate receptors, based on the structural featuresof the receptor proteins, the means by which the receptors transducesignals into the cell, and pharmacological profiles.

The metabotropic glutamate receptors (mGluRs) are G protein-coupledreceptors that activate a variety of intracellular second messengersystems following the binding of glutamate. Activation of mGluRs inintact mammalian neurons elicits one or more of the following responses:activation of phospholipase C; increases in phosphoinositide (PI)hydrolysis; intracellular calcium release; activation of phospholipaseD; activation or inhibition of adenyl cyclase; increases or decreases inthe formation of cyclic adenosine monophosphate (cAMP); activation ofguanylyl cyclase; increases in the formation of cyclic guanosinemonophosphate (cGMP); activation of phospholipase A₂; increases inarachidonic acid release; and increases or decreases in the activity ofvoltage- and ligand-gated ion channels. Schoepp et al., TrendsPharmacol. Sci. 14:13 (1993), Schoepp, Neurochem. Int. 24:439 (1994),Pin et al., Neuropharmacology 34:1 (1995), Bordi and Ugolini, Prog.Neurobiol. 59:55 (1999).

Molecular cloning has identified eight distinct mGluR subtypes, termedmGluR1 through mGluR8. Nakanishi, Neuron 13:1031 (1994), Pin et al.,Neuropharmacology 34:1 (1995), Knopfel et al., J. Med. Chem. 38:1417(1995). Further receptor diversity occurs via expression ofalternatively spliced forms of certain mGluR subtypes. Pin et al., PNAS89:10331 (1992), Minakami et al., BBRC 199:1136 (1994), Joly et al., J.Neurosci. 15:3970 (1995).

Metabotropic glutamate receptor subtypes may be subdivided into threegroups, Group I, Group II, and Group III mGluRs, based on amino acidsequence homology, the second messenger systems utilized by thereceptors, and by their pharmacological characteristics. Group I mGluRcomprises mGluR1, mGluR5 and their alternatively spliced variants. Thebinding of agonists to these receptors results in the activation ofphospholipase C and the subsequent mobilization of intracellularcalcium.

Neurological, Psychiatric and Pain Disorders

Attempts at elucidating the physiological roles of Group I mGluRssuggest that activation of these receptors elicits neuronal excitation.Various studies have demonstrated that Group I mGluRs agonists canproduce postsynaptic excitation upon application to neurons in thehippocampus, cerebral cortex, cerebellum, and thalamus, as well as otherCNS regions. Evidence indicates that this excitation is due to directactivation of postsynaptic mGluRs, but it also has been suggested thatactivation of presynaptic mGluRs occurs, resulting in increasedneurotransmitter release. Baskys, Trends Pharmacol. Sci. 15:92 (1992),Schoepp, Neurochem. Int. 24:439 (1994), Pin et al., Neuropharmacology34:1(1995), Watkins et al., Trends Pharmacol. Sci. 15:33 (1994).

Metabotropic glutamate receptors have been implicated in a number ofnormal processes in the mammalian CNS. Activation of mGluRs has beenshown to be required for induction of hippocampal long-term potentiationand cerebellar long-term depression. Bashir et al., Nature 363:347(1993), Bortolotto et al., Nature 368:740 (1994), Aiba et al., Cell79:365 (1994), Aiba et al., Cell 79:377 (1994). A role for mGluRactivation in nociception and analgesia also has been demonstrated,Meller et al., Neuroreport 4: 879 (1993), Bordi and Ugolini, Brain Res.871:223 (1999). In addition, mGluR activation has been suggested to playa modulatory role in a variety of other normal processes includingsynaptic transmission, neuronal development, apoptotic neuronal death,synaptic plasticity, spatial learning, olfactory memory, central controlof cardiac activity, waking, motor control and control of thevestibulo-ocular reflex. Nakanishi, Neuron 13: 1031 (1994), Pin et al.,Neuropharmacology 34:1, Knopfel et al., J. Med. Chem. 38:1417 (1995).

Further, Group I metabotropic glutamate receptors and mGluR5 inparticular, have been suggested to play roles in a variety ofpathophysiological processes and disorders affecting the CNS. Theseinclude stroke, head trauma, anoxic and ischemic injuries, hypoglycemia,epilepsy, neurodegenerative disorders such as Alzheimer's disease andpain. Schoepp et al., Trends Pharmacol. Sci. 14:13 (1993), Cunningham etal., Life Sci. 54:135 (1994), Hollman et al., Ann. Rev. Neurosci. 17:31(1994), Pin et al., Neuropharmacology 34:1 (1995), Knopfel et al., J.Med. Chem. 38:1417 (1995), Spooren et al., Trends Pharmacol. Sci. 22:331(2001), Gasparini et al. Curr. Opin. Pharmacol. 2:43 (2002), NeugebauerPain 98:1 (2002). Much of the pathology in these conditions is thoughtto be due to excessive glutamate-induced excitation of CNS neurons.Because Group I mGluRs appear to increase glutamate-mediated neuronalexcitation via postsynaptic mechanisms and enhanced presynapticglutamate release, their activation probably contributes to thepathology. Accordingly, selective antagonists of Group I mGluR receptorscould be therapeutically beneficial, specifically as neuroprotectiveagents, analgesics or anticonvulsants.

Recent advances in the elucidation of the neurophysiological roles ofmetabotropic glutamate receptors generally and Group I in particular,have established these receptors as promising drug targets in thetherapy of acute and chronic neurological and psychiatric disorders andchronic and acute pain disorders.

Gastrointestinal Disorders

The lower esophageal sphincter (LES) is prone to relaxingintermittently. As a consequence, fluid from the stomach can pass intothe esophagus since the mechanical barrier is temporarily lost at suchtimes, an event hereinafter referred to as “reflux”.

Gastro-esophageal reflux disease (GERD) is the most prevalent uppergastrointestinal tract disease. Current pharmacotherapy aims at reducinggastric acid secretion, or at neutralizing acid in the esophagus. Themajor mechanism behind reflux has been considered to depend on ahypotonic lower esophageal sphincter. However, e.g. Holloway & Dent(1990) Gastroenterol. Clin. N. Amer. 19, pp. 517-535, has shown thatmost reflux episodes occur during transient lower esophageal sphincterrelaxations (TLESRs), i.e. relaxations not triggered by swallows. It hasalso been shown that gastric acid secretion usually is normal inpatients with GERD.

The novel compounds according to the present invention are assumed to beuseful for the inhibition of transient lower esophageal sphincterrelaxations (TLESRs) and thus for treatment of gastro-esophageal refluxdisorder (GERD).

Because of their physiological and pathophysiological significance,there is a need for new potent mGluR agonists and antagonists thatdisplay a high selectivity for mGluR subtypes, particularly the Group Ireceptor subtype, most particularly the mGluR5

The object of the present invention is to provide compounds exhibitingan activity at metabotropic glutamate receptors (mGluRs), especially atthe mGluR5 receptor.

DESCRIPTION OF THE INVENTION

One embodiment of the present invention relates to a compound of formulaI:

as well as pharmaceutically acceptable salts, hydrates, isoforms and/orenantiomers thereof. In one embodiment, the compound of formula I is theR-enantiomer. In another embodiment, the compound of formula I is theS-enantiomer.

A further embodiment of the present invention relates to a compound offormula II:

as well as pharmaceutically acceptable salts, hydrates and/or isoformsthereof.

Yet another embodiment of the present invention relates to a compound offormula III:

as well as pharmaceutically acceptable salts, hydrates and/or isoformsthereof.

Another embodiment is a pharmaceutical composition comprising as activeingredient a therapeutically effective amount of the compound accordingto formula I-III, in association with one or more pharmaceuticallyacceptable diluents, excipients and/or inert carriers.

Other embodiments, as described in more detail below, relate to acompound according to formula I-III for use in therapy, in treatment ofmGluR5 mediated disorders, in the manufacture of a medicament for thetreatment of mGluR5 mediated disorders.

Still other embodiments relate to a method of treatment of mGluR5mediated disorders, comprising administering to a mammal atherapeutically effective amount of the compound according according toformula I-III.

In another embodiment, there is provided a method for inhibitingactivation of mGlurR5 receptors, comprising treating a cell containingsaid receptor with an effective amount of the compound according toformula I-III.

The compounds of the present invention are useful in therapy, inparticular for the treatment of neurological, psychiatric, pain, andgastrointestinal disorders.

It will also be understood by those of skill in the art that certaincompounds of the present invention may exist in solvated, for examplehydrated, as well as unsolvated forms. It will further be understoodthat the present invention encompasses all such solvated forms of thecompounds of formula I-III.

Within the scope of the invention are also salts of the compounds offormula I-III. Generally, pharmaceutically acceptable salts of compoundsof the present invention are obtained using standard procedures wellknown in the art, for example, by reacting a sufficiently basiccompound, for example an alkyl amine with a suitable acid, for example,HCl or acetic acid, to afford a salt with a physiologically acceptableanion. It is also possible to make a corresponding alkali metal (such assodium, potassium, or lithium) or an alkaline earth metal (such as acalcium) salt by treating a compound of the present invention having asuitably acidic proton, such as a carboxylic acid or a phenol, with oneequivalent of an alkali metal or alkaline earth metal hydroxide oralkoxide (such as the ethoxide or methoxide), or a suitably basicorganic amine (such as choline or meglumine) in an aqueous medium,followed by conventional purification techniques. Additionally,quaternary ammonium salts can be prepared by the addition of alkylatingagents, for example, to neutral amines.

In one embodiment of the present invention, the compound of formulaI-III may be converted to a pharmaceutically acceptable salt or solvatethereof, particularly, an acid addition salt such as a hydrochloride,hydrobromide, phosphate, acetate, fumarate, maleate, tartrate, citrate,methanesulphonate or p-toluenesulphonate.

In further embodiments of the present invention, the compound of formulaI-III may be converted to a pharmaceutically acceptable salt or solvatethereof with sulfonic acid, 1,2-ethanedisulfonic acid (both as 1:1 and2:1), ethanesulfonic acid, nitric acid, 2-mesitylenesulfonic acid,1,5-naphthalenedisulfonic acid (both as 1:1 and 2:1) or p-xylenesulfonicacid.

Pharmaceutical Composition

The compounds of the present invention may be formulated intoconventional pharmaceutical compositions comprising a compound offormula I-III, or a pharmaceutically acceptable salt or solvate thereof,in association with a pharmaceutically acceptable carrier or excipient.The pharmaceutically acceptable carriers can be either solid or liquid.Solid form preparations include, but are not limited to, powders,tablets, dispersible granules, capsules, cachets, and suppositories.

A solid carrier can be one or more substances, which may also act asdiluents, flavoring agents, solubilizers, lubricants, suspending agents,binders, or tablet disintegrating agents. A solid carrier can also be anencapsulating material.

In powders, the carrier is a finely divided solid, which is in a mixturewith the finely divided compound of the invention, or the activecomponent. In tablets, the active component is mixed with the carrierhaving the necessary binding properties in suitable proportions andcompacted in the shape and size desired.

For preparing suppository compositions, a low-melting wax such as amixture of fatty acid glycerides and cocoa butter is first melted andthe active ingredient is dispersed therein by, for example, stirring.The molten homogeneous mixture is then poured into convenient sizedmoulds and allowed to cool and solidify.

Suitable carriers include, but are not limited to, magnesium carbonate,magnesium stearate, talc, lactose, sugar, pectin, dextrin, starch,tragacanth, methyl cellulose, sodium carboxymethyl cellulose,low-melting wax, cocoa butter, and the like.

The term composition is also intended to include the formulation of theactive component with encapsulating material as a carrier providing acapsule in which the active component (with or without other carriers)is surrounded by a carrier which is thus in association with it.Similarly, cachets are included.

Tablets, powders, cachets, and capsules can be used as solid dosageforms suitable for oral administration.

Liquid form compositions include solutions, suspensions, and emulsions.For example, sterile water or water propylene glycol solutions of theactive compounds may be liquid preparations suitable for parenteraladministration. Liquid compositions can also be formulated in solutionin aqueous polyethylene glycol solution.

Aqueous solutions for oral administration can be prepared by dissolvingthe active component in water and adding suitable colorants, flavoringagents, stabilizers, and thickening agents as desired. Aqueoussuspensions for oral use can be made by dispersing the finely dividedactive component in water together with a viscous material such asnatural synthetic gums, resins, methyl cellulose, sodium carboxymethylcellulose, and other suspending agents known to the pharmaceuticalformulation art. Exemplary compositions intended for oral use maycontain one or more coloring, sweetening, flavoring and/or preservativeagents.

Depending on the mode of administration, the pharmaceutical compositionwill include from about 0.05% w (percent by weight) to about 99% w, orfrom about 0.10% w to 50% w, of a compound of the invention, allpercentages by weight being based on the total weight of thecomposition.

A therapeutically effective amount for the practice of the presentinvention can be determined by one of ordinary skill in the art usingknown criteria including the age, weight and response of the individualpatient, and interpreted within the context of the disease which isbeing treated or which is being prevented.

Medical Use

The compounds according to the present invention are useful in thetreatment of conditions associated with excitatory activation of mGluR5and for inhibiting neuronal damage caused by excitatory activation ofmGluR5. The compounds may be used to produce an inhibitory effect ofmGluR5 in mammals, including man.

The Group I mGluR receptors including mGluR5 are highly expressed in thecentral and peripheral nervous system and in other tissues. Thus, it isexpected that the compounds of the invention are well suited for thetreatment of mGluR5-mediated disorders such as acute and chronicneurological and psychiatric disorders, gastrointestinal disorders, andchronic and acute pain disorders.

The invention relates to compounds of Formula I-III, as definedhereinbefore, for use in therapy.

The invention relates to compounds of Formula I-III, as definedhereinbefore, for use in treatment of mGluR5-mediated disorders.

The invention relates to compounds of Formula I-III, as definedhereinbefore, for use in treatment of Alzheimer's disease seniledementia, AIDS-induced dementia, Parkinson's disease, amylotropiclateral sclerosis, Huntington's Chorea, migraine, epilepsy,schizophrenia, depression, anxiety, acute anxiety, ophthalmologicaldisorders such as retinopathies, diabetic retinopathies, glaucoma,auditory neuropathic disorders such as tinnitus, chemotherapy inducedneuropathies, post-herpetic neuralgia and trigeminal neuralgia,tolerance, dependency, Fragile X, autism, mental retardation,schizophrenia and Down's Syndrome.

The invention relates to compounds of Formula I-III, as defined above,for use in treatment of pain related to migraine, inflammatory pain,neuropathic pain disorders such as diabetic neuropathies, arthritis andrheumatiod diseases, low back pain, post-operative pain and painassociated with various conditions including cancer, angina, renal orbilliary colic, menstruation, migraine and gout.

The invention relates to compounds of Formula I-III as definedhereinbefore, for use in treatment of stroke, head trauma, anoxic andischemic injuries, hypoglycemia, cardiovascular diseases and epilepsy.

The present invention relates also to the use of a compound of FormulaI-III as defined hereinbefore, in the manufacture of a medicament forthe treatment of mGluR Group I receptor-mediated disorders and anydisorder listed above.

One embodiment of the invention relates to the use of a compoundaccording to Formula I-III in the treatment of gastrointestinaldisorders.

Another embodiment of the invention relates to the use of a FormulaI-III compound for the manufacture of a medicament for inhibition oftransient lower esophageal sphincter relaxations, for the treatment ofGERD, for the prevention of gastroesophageal reflux, for the treatmentregurgitation, for treatment of asthma, for treatment of laryngitis, fortreatment of lung disease, for the management of failure to thrive, forthe treatment of irritable bowel disease (IBS) and for the treatment offunctional dyspepsia (FD).

The wording “TLESR”, transient lower esophageal sphincter relaxations,is herein defined in accordance with Mittal, R. K, Holloway, R. H.,Penagini, R., Blackshaw, L. A., Dent, J, 1995, Transient loweresophageal sphincter relaxation. Gastroenterology 109, pp. 601-610.

The wording “reflux” is herein defined as fluid from the stomach beingable to pass into the esophagus, since the mechanical barrier istemporarily lost at such times.

The wording “GERD”, gastro-esophageal reflux disease, is herein definedin accordance with van Heerwarden, M. A., Smout A. J. P. M, 2000,Diagnosis of reflux disease. Bailliére 's Clin. Gastroenterol. 14, pp.759-774.

A further embodiment of the invention relates to the use of a compoundaccording to Formula I-III for the manufacture of a medicament for thetreatment of cough. In one embodiment, the cough to be treated ischronic cough. In a further embodiment, the cough to be treated is acutecough. The term chronic cough is defined in accordance with Kardos P etal (The German Respiratory Society's Guideline for the Diagnosis andTreatment of Patients with Acute and Chronic Cough Medizinische Klinik2004; 99(8):468-75) as a cough that lasts longer than 8 weeks. However,chronic cough can also be defined as a cough lasting longer than 3 weeksor as a cough lasting longer than 2 months. The term “acute cough” isalso defined in accordance with the reference above as a cough lastingless than 8 weeks.

The compounds of formula I-III above are useful for the treatment orprevention of obesity or overweight, (e.g., promotion of weight loss andmaintenance of weight loss), prevention or reversal of weight gain(e.g., rebound, medication-induced or subsequent to cessation ofsmoking), for modulation of appetite and/or satiety, eating disorders(e.g. binge eating, anorexia, bulimia and compulsive) and cravings (fordrugs, tobacco, alcohol, any appetizing macronutrients or non-essentialfood items).

The invention also provides a method of treatment of mGluR5-mediateddisorders and any disorder listed above, in a patient suffering from, orat risk of, said condition, which comprises administering to the patientan effective amount of a compound of Formula I-III, as hereinbeforedefined.

The dose required for the therapeutic or preventive treatment of aparticular disorder will necessarily be varied depending on the hosttreated, the route of administration and the severity of the illnessbeing treated.

In the context of the present specification, the term “therapy” and“treatment” includes prevention or prophylaxis, unless there arespecific indications to the contrary. The terms “therapeutic” and“therapeutically” should be construed accordingly.

In this specification, unless stated otherwise, the term “antagonist”and “inhibitor” shall mean a compound that by any means, partly orcompletely, blocks the transduction pathway leading to the production ofa response by the ligand.

The term “disorder”, unless stated otherwise, means any condition anddisease associated with metabotropic glutamate receptor activity.

Non-Medical Use

In addition to their use in therapeutic medicine, the compounds ofFormula I-III, as well as salts and hydrates of such compounds, areuseful as pharmacological tools in the development and standardisationof in vitro and in vivo test systems for the evaluation of the effectsof inhibitors of mGluR related activity in laboratory animals such ascats, dogs, rabbits, monkeys, rats and mice, as part of the search fornew therapeutic agents.

Methods of Preparation

Synthesis of Intermediates

Synthesis of Final Compounds

General Methods

All starting materials are commercially available or earlier describedin the literature.

The ¹H and ¹³C NMR spectra were recorded either on Bruker 300, BrukerDPX400 or Varian+400 spectrometers operating at 300, 400 and 400 MHz for¹H NMR respectively, using TMS or the residual solvent signal asreference, in deuterated chloroform as solvent unless otherwiseindicated. All reported chemical shifts are in ppm on the delta-scale,and the fine splitting of the signals as appearing in the recordings (s:singlet, br s: broad singlet, d: doublet, t: triplet, q: quartet, m:multiplet).

Analytical in line liquid chromatography separations followed by massspectra detections, were recorded on a Waters LC-MS consisting of anAlliance 2795 (LC) and a ZQ single quadropole mass spectrometer. Themass spectrometer was equipped with an electrospray ion source operatedin a positive and/or negative ion mode. The ion spray voltage was ±3 kVand the mass spectrometer was scanned from m/z 100-700 at a scan time of0.8 s. To the column, X-Terra MS, Waters, C8, 2.1×50 mm, 3.5 μm, wasapplied a linear gradient from 5% to 100% acetonitrile in 10 mM ammoniumacetate (aq.), or in 0.1% TFA (aq.).

Optical rotation was measured with a Perkin Elmer 241 polarimeter, usinga 10 cm cell at 23° C. at 589 nm.

List of Abbreviations

-   -   aq. Aqueous    -   DMF dimethyl formamide    -   EtOAc ethyl acetate    -   NH₄Cl ammonium chloride    -   Novozyme 435® Registered trademark name for polymer bound        candida antarctica lipase    -   r.t. or RT room temperature (unless otherwise stated, a        temperature between 16 to 26° C.)

EXAMPLES

Synthesis of Intermediates

Example 1 Ethyl 4-(3-chlorophenyl)-2,4-dioxobutanoate

Sodium ethoxide (117.8 g, 1.73 mol) was added in portions to a solutionof 3-chloroacetophenone (178.5 g, 1.15 mol) and diethyl oxalate (188 mL,1.39 mol) in ethanol (3 L) at 0° C. The mixture was stirred at roomtemperature for 1 h and was then heated at 70° C. for 2 h. Aftercooling, the mixture was acidified with 3M hydrochloric acid (pH˜3). Thesolvent was distilled off and to the mixture was added EtOAc. Theorganic layer was washed with water and saturated brine. The solvent wasdistilled off to give crude title product, which was used directly inthe next step. MS (M⁺−1)=253.

Example 2 Ethyl 5-(3-chlorophenyl)isoxazole-3-carboxylate

A solution of crude ethyl 4-(3-chlorophenyl)-2,4-dioxobutanoate (max 294g, 1.16 mol) and hydroxylamine hydrochloride (120.4 g, 1.73 mol) inethanol (4 L) was heated at 80° C. for 4 h. After cooling (over night)to ca 5-10° C., the mixture was filtered, washed with cold ethanol anddried in vacuo to afford the title compound (214.5 g, 74%). ¹H NMR: 7.82(s, 1H), 7.72 (m, 1H), 7.47 (m, 2H), 4.03 (s, 3H). MS (M⁺+1)=252.

Example 3 [5-(3-chlorophenyl)isoxazol-3-yl]methanol

Sodium borohydride (96.7 g, 2.6 mol) was slowly added to a solution ofethyl 5-(3-chlorophenyl)isoxazole-3-carboxylate (214.5 g, 0.85 mol) inmethanol (2.5 L) at 0° C. The reaction mixture was heated at 50° C. for2 h and was quenched with EtOAc at r.t. Most of the solvent wasdistilled off and to the remaining crude was added EtOAc. The organiclayer was washed with water, saturated brine and concentrated to givethe title compound, which was used directly in the next step. MS(M⁺+1)=210.

Example 4 5-(3-chlorophenyl)isoxazole-3-carbaldehyde

[5-(3-chlorophenyl)isoxazol-3-yl]methanol (178.6 g, 852 mmol) indichloromethane (2 L) was dropwise added to pyridinium chlorochromate(400 g, 1.86 mol) in dichloromethane (2 L). The resulting slurry wasstirred over night at room temperature. The slurry was filtrated throughcelite and the filtrate was distilled off. To the remaining solutionEtOAc was added. The organic layer was washed with water, saturatedbrine and concentrated, to give crude title compound, which was useddirectly in the next step. ¹H NMR (DMSO-d₆): 10.13 (s, 1H), 8.08 (br s,1H), 7.95 (m, 1H), 7.61 (m, 3H). MS (M⁺+1)=208.

Example 5 1-[5-(3-chlorophenyl)isoxazol-3-yl]ethanol

MeMgBr (3M in THF, 313 mL, 937.2 mmol) was added dropwise at 0° C. to5-(3-chlorophenyl)isoxazole-3-carbaldehyde (177 g, 252 mmol) in THF (3L). The mixture was allowed to attain room temperature, stirred at thattemperature for 3 h and then quenched with aq. NH₄Cl at 0° C. and thesolvent was distilled off. To the remaining was added EtOAc and filteredthrough a plug of celite. The organic layer was washed with water,saturated brine and concentrated. The crude product was purified byflash column chromatography on silica using heptane/EtOAc=80:20, to givethe title compound (70 g, 37%) as a white-yellow solid. ¹H NMR: 7.73 (m,1 H), 7.63 (m, 1 H), 7.38 (m, 2 H), 6.57 (s, 1 H), 5.07 (q, 1 H), 2.44(s, 1 H), 1.59 (d, 3 H).

Example 6 (1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethyl acetate

1-[5-(3-chlorophenyl)isoxazol-3-yl]ethanol (106.5 g, 476 mmol) andNovozyme 435® (13 g) are taken up under Ar in dry toluene (1.5 L). Afteraddition of vinyl acetate (66 mL, 716 mmol) the reaction was run at r.t.over night, followed by filtration over celite and washing with DCM. Thesolvent was evaporated in vacuo and the crude product was subjected tocolumn chromatography on silica using dichloromethane/methanol=20:1, togive the title compound (50 g, 47%). ¹H NMR: 7.76 (m, 1H), 7.65 (m, 1H),7.41 (m, 2H), 6.54 (s, 1H), 6.07 (q, 1H), 2.13 (s, 3H), 1.66 (d, 3H).LC-MS (M⁺+1)=266.

Example 7

(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethanol

(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethyl acetate (56 g, 211 mmol)and lithium hydroxide monohydrate (10.6 g, 253 mmol) were mixed withTHF/Water (7/5, 1.2 L) and stirred at r.t. over night. Reducing thevolume of the mixture in vacuo to about ½, followed by dilution withbrine, extraction with ether and then drying over MgSO₄ and in vacuoconcentration gave crude product. The crude product was purified byflash column chromatography on silica using heptane/EtOAc=70:30, to givethe title compound (40 g, 85%). ¹H NMR: 7.73 (m, 1 H), 7.63 (m, 1 H),7.38 (m, 2 H), 6.57 (s, 1 H), 5.07 (q, 1 H), 2.44 (s, 1 H), 1.59 (d, 3H).

Example 8 2-Isonicotinoyl-N-methylhydrazinecarbothioamide

To a gently heated (35° C.) and mechanically stirred suspension ofisonicotinohydrazide (435 g) in isopropyl alcohol (6.0 L) was added(methylimino)(thioxo)methane (230 g) in several small portions. Aftercomplete addition, the reaction mixture was heated (70° C.) for 6 h withan additional addition of isopropyl alcohol (600 ml) after 30 min. Aftercooling (ice-bath) the reaction mixture to 17° C., the obtainedprecipitate was filtered off and washed with isopropyl alcohol (1.0 L).This solid was then air-dried over night to provide 615 g of the titlecompound as a white powder.

Example 9 4-Methyl-5-pyridin-4-yl-2,4-dihydro-3H-1,2,4-triazole-3-thione

To a mechanically stirred suspension of2-isonicotinoyl-N-methylhydrazinecarbothioamide (610 g) in water (5.0 L)was added sodium bicarbonate (390 g) at r.t. The reaction mixture wasthereafter slowly heated to 70° C. over 2 h, and maintained at thattemperature for another 3.5 h before cooling (ice-bath) to 17° C.,followed by adjusting the pH to 3 by slow addition (over 90 min) ofconcentrated hydrochloric acid (ca. 470 mL). Subsequent filtration ofthe reaction mixture, followed by washing the collected solid withdilute hydrochloric acid (0.1 N, 2×1.0 L), gave a wet cake that wasdried at 100 mbar under a gentle stream of air for 1.5 days to yield 544g of the title compound.

Example 10 4-[4-Methyl-5-(methylthio)-4H-1,2,4-triazol-3-yl]pyridine

To a mechanically stirred and cooled (9° C.) suspension of4-methyl-5-pyridin-4-yl-2,4-dihydro-3H-1,2,4-triazole-3-thione (267 g)and methyl iodide (197.7 g) in acetone (2.6 L), was added a solution ofsodium hydroxide (54 g in 600 mL of water) at such a rate (ca. 20 mLmin) as to maintain the temperature between 10 and 15° C. Anotherportion of water (50 mL) was then added and the temperature was allowedto come to 21 to 24° C. After another 2 h, the acetone was distilled offfrom the reaction mixture in vacuo (water-bath kept at 30° C.). Anotherportion of water (750 mL) was then added before cooling (17 to 18° C.)and collection of the formed precipitate by filtration. This solid wasthen washed with water (2×1 L) before drying at 100 mbar under a gentlestream of air for 3 days to yield 235 g of the title compound as a whitepowder. ¹H NMR (DMSO-d₆): 2.7 (s, 3 H) 3.6 (s, 3 H) 7.7 (m, 2 H) 8.8 (d,2 H).

Example 11 4-[4-Methyl-5-(methylsulfonyl)-4H-1,2,4-triazol-3-yl]pyridine

To a mechanically stirred solution of4-[4-methyl-5-(methylthio)-4H-1,2,4-triazol-3-yl]pyridine (228 g) fromthe previous step, in a mixture of water (1.15 L) and acetic acid (1.15L), was added portion-wise while cooling potassium permanganate (234 g),at such a rate as to maintain the temperature between 12 to 17° C. (ca.45 min). The reaction mixture was then stirred at r.t. for 4 h beforecooling on an ice-bath during the addition of a sodium hydroxidesolution (5 N) over 2.5 h to set the pH to ca. 10. Dicalite® (100 g) andchloroform (1.6 L) was then added to the reaction mixture beforefiltration. The organic phase was separated from the filtrate and theaq. phase from the same was extracted with chloroform (2×1 L). Thefilter-cake was extracted twice with chloroform (2×1.5 L). The combinedorganic phases were dried over magnesium sulfate, filtered, andconcentrated in vacuo to provide 158 g of the title compound as a whitepowder. Another crop (78 g, white powder) was obtained by extraction ofthe filter cake with chloroform (2×2 L) and concentration of thissolution in vacuo. ¹H NMR (DMSO-d₆): 3.6 (s, 3 H) 3.9 (s, 3 H) 7.8 (s, 2H) 8.8 (s, 2 H).

Example 12 3-[4-methyl-5-(methylsulfonyl)-4H-1,2,4-triazol-3-yl]pyridine

The title compound was prepared analogously to4-[4-methyl-5-(methylsulfonyl)-4H-1,2,4-triazol-3-yl]pyridine asdescribed herein, via the corresponding sequence consisting of thecorresponding steps, by starting from nicotinohydrazide instead ofisonicotinohydrazide. ¹H NMR: 3.59 (s, 3H) 3.99 (s, 3H) 7.52 (m, 1H)8.02 (dt, 1H) 8.83 (dd, 1H) 8.91 (m, 1H).

Synthesis of Final Compounds

Example 133-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridine

(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethanol (5.40 g, 24.1 mmol) wasdissolved in DMF (45 mL). To this3-[4-methyl-5-(methylsulfonyl)-4H-1,2,4-triazol-3-yl]pyridine (5.75 g,24.1 mmol) and cesium carbonate (10.1 g, 31.4 mmol) were added. Afterstirring over night at 60° C., water was added. The mixture wasextracted with dichloromethane, followed by concentration of the organiclayer in vacuo, to give a crude which was purified by columnchromatography on silica using dichloromethane/methanol=98/2, to givethe title compound (7.10 g, 77%). ¹H NMR: 8.90 (d, 1H), 8.72 (m, 1H),8.04 (dt, 1H), 7.76 (bs, 1H), 7.66 (m, 1H), 7.45 (m, 1H), 7.40 (m, 2H),6.73 (s, 1H), 6.35 (q, 1H), 3.57 (s, 3H), 1.93 (d, 3H). ¹H NMR(DMSO-d₆): 8.90 (d, 1H), 8.71 (dd, 1H), 8.13 (dt, 1H), 7.99 (s, 1H),7.86 (m, 1H), 7.58 (m, 3H), 7.40 (s, 1H), 6.19 (q, 1H), 3.54 (s, 3H),1.81 (d, 3H). LC-MS (M⁺+1)=382. [α]_(D) ^(RT)(2.92 g/L, CDCl₃)=−46.575°

Example 144-(5-{(rac)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridine

1-[5-(3-chlorophenyl)isoxazol-3-yl]ethanol (63.4 mg, 0.28 mmol), DMF andsodium hydride (60% dispersion in oil, 15.1 mg, 0.38 mmol) were mixedunder inert atmosphere and stirred at r.t for 1 h, followed by additionof 4-[4-methyl-5-(methylsulfonyl)-4H-1,2,4-triazol-3-yl]pyridine (45 mg,0.19 mmol). After stirring at 80° C. for 24 h, the mixture was cooled tor.t., diluted with EtOAc and washed with water and brine. The organicphase was dried (Na₂SO₄), filtered and concentrated in vacuo. The cruderesidue was purified via column chromatography on silica using 5%methanol in EtOAc to isolate the title compound (11.7 mg). ¹H-NMR: 8.81(bs, 2H), 7.77 (s, 1H), 7.67 (m, 3H), 7.42 (m, 2H), 6.73 (s, 1H), 6.36(q, 1H), 3.62 (s, 3H), 1.94 (d, 3H).

Example 154-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridine

Method 1: Preparative chiral HPLC separation of4-(5-{(rac)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridineon chiralpak AD column with isopropranol as eluent, yielded the titlecompound as the first eluting enantiomer.

Method 2: The title compound was prepared analogous to3-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridine,by coupling of (1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethanol with4-[4-methyl-5-(methylsulfonyl)-4H-1,2,4-triazol-3-yl]pyridine employingcesium carbonate in DMF. ¹H NMR (DMSO-d₆): 8.73 (m, 2H), 7.97 (br. s,1H), 7.85 (m, 1H), 7.74 (m, 2H), 7.58 (m, 2H), 7.39 (s, 1H), 6.20 (q,1H), 3.60 (s, 3H), 1.81 (d, 3H). [α]_(D) ^(RT) (5.827 g/L,CDCl₃)=−48.567°

Example 164-(5-{(1S)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridine

The title compound was isolated as the second eluting enantiomer inpreparative chiral HPLC separation as described in the example of4-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3yl)pyridine(method 1). ¹H-NMR: 8.81 (bs, 2H), 7.77 (s, 1H), 7.67 (m, 3H), 7.42 (m,2H), 6.73 (s, 1H), 6.36 (q, 1H), 3.62 (s, 3H), 1.94 (d, 3H).

Example 174-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridinehydrochloride

The title salt was manufactured by adding 1 μl of a 32 wt-% aqueous HClsolution in two portions to a clear solution of 35 mg4-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridinefree base in 500 μl ethanol at 50° C. The slurry was cooled to 10° C.and kept over night under agitation before the salt was filtered off,washed with 500 μl ethanol and dried at room temperature under vacuum.

The salt was crystalline, had a clear melting behaviour and had anincreased moisture sorption at 90-95% RH.

The title salt was manufactured again in a similar way in ethanol,2-propanol and ethyl acetate and also at 1 g scale in ethanol. Allbatches produced the same crystal modification, although the amorphouscontent was slightly higher in some batches. The melting point was from150° C. to 160° C.

The salt manufactured at 1 g scale from ethanol was further investigatedfor its intrinsic dissolution rate and compared to the free base of4-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridine.The salt had a 1000 times higher intrinsic dissolution rate as comparedto the free base. Dissolution rates of the base and salt were measuredwith a low-volume rotating disc method. Discs were compressed from purecompound and centrically mounted in a disc holder with an exposed areaof 0.07 cm². The disc holder rotated at 500 rpm immersed in 50 mL USPPhosphate buffer pH 6.8 at 37° C. The compound was analysed UV-Online bya Spectrophotometer with a flow cell and a peristaltic pump withcontinuous circulation.

Example 184-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridinesulphate

An oiled salt was manufactured by evaporating a clear solution obtainedby mixing 500 μl water with 33 mg4-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridinefree base, 500 μl methanol and 7 μl 98 wt-% sulphuric acid. The titlesalt was manufactured by recrystallising the oiled salt in 500 μlethanol.

The title salt was crystalline with essential amorphous content, had noclear melting behaviour and deliquesce at 60-70% relative humidity.

The title salt was manufactured again by adding three portions of 5 μlconcentrated sulphuric acid (98%) over 1.5 h to a clear solution of66-68 mg4-(5-{(1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethoxy}-4-methyl-4H-1,2,4-triazol-3-yl)pyridinefree base in 1 ml 2-propanol or 1 ml ethanol at 68° C. The saltmanufactured from ethanol had a melting point of 128° C. although itdeliquesce at 70-80% RH.

Biological Evaluation

Functional Assessment of mGluR5 Antagonism in Cell Lines ExpressingmGluR5D

The properties of the compounds of the invention can be analyzed usingstandard assays for pharmacological activity. Examples of glutamatereceptor assays are well known in the art as described in for exampleAramori et al., Neuron 8:757 (1992), Tanabe et al., Neuron 8:169 (1992),Miller et al., J. Neuroscience 15: 6103 (1995), Balazs, et al., J.Neurochemistry 69:151 (1997). The methodology described in thesepublications is incorporated herein by reference. Conveniently, thecompounds of the invention can be studied by means of an assay (FLIPR)that measures the mobilization of intracellular calcium, [Ca²⁺]_(i) incells expressing mGluR5 or another assay (IP3) that measures inositolphosphate turnover.

FLIPR Assay

Cells expressing human mGluR5d as described in WO97/05252 are seeded ata density of 100,000 cells per well on collagen coated clear bottom96-well plates with black sides and experiments are done 24 h followingseeding. All assays are done in a buffer containing 127 mM NaCl, 5 mMKCl, 2 mM MgCl₂, 0.7 mM NaH₂PO₄, 2 mM CaCl₂, 0.422 mg/ml NaHCO₃, 2.4mg/ml HEPES, 1.8 mg/ml glucose and 1 mg/ml BSA Fraction IV (pH 7.4).Cell cultures in the 96-well plates are loaded for 60 minutes in theabove mentioned buffer containing 4 μM of the acetoxymethyl ester formof the fluorescent calcium indicator fluo-3 (Molecular Probes, Eugene,Oreg.) in 0.01% pluronic acid (a proprietary, non-ionic surfactantpolyol—CAS Number 9003-11-6). Following the loading period the fluo-3buffer is removed and replaced with fresh assay buffer. FLIPRexperiments are done using a laser setting of 0.800 W and a 0.4 secondCCD camera shutter speed with excitation and emission wavelengths of 488nm and 562 nm, respectively. Each experiment is initiated with 160 μl ofbuffer present in each well of the cell plate. A 40 μl addition from theantagonist plate was followed by a 50 μL addition from the agonistplate. A 90 second interval separates the antagonist and agonistadditions. The fluorescence signal is sampled 50 times at 1 secondintervals followed by 3 samples at 5 second intervals immediately aftereach of the two additions. Responses are measured as the differencebetween the peak height of the response to agonist, less the backgroundfluorescence within the sample period. IC₅₀ determinations are madeusing a linear least squares fitting program.

IP3 Assay

An additional functional assay for mGluR5d is described in WO97/05252and is based on phosphatidylinositol turnover. Receptor activationstimulates phospholipase C activity and leads to increased formation ofinositol 1,4,5,triphosphate (IP₃).

GHEK stably expressing the human mGluR5d are seeded onto 24 wellpoly-L-lysine coated plates at 40×10⁴ cells /well in media containing 1μCi/well [3H] myo-inositol. Cells were incubated overnight (16 h), thenwashed three times and incubated for 1 h at 37° C. in HEPES bufferedsaline (146 mM NaCl, 4.2 mM KCl, 0.5 mM MgCl₂, 0.1% glucose, 20 mMHEPES, pH 7.4) supplemented with 1 unit/ml glutamate pyruvatetransaminase and 2 mM pyruvate. Cells are washed once in HEPES bufferedsaline and pre-incubated for 10 min in HEPES buffered saline containing10 mM LiCl. Compounds are incubated in duplicate at 37° C. for 15 min,then either glutamate (80 μM) or DHPG (30 μM) is added and incubated foran additional 30 min. The reaction is terminated by the addition of 0.5ml perchloric acid (5%) on ice, with incubation at 4° C. for at least 30min. Samples are collected in 15 ml polyproplylene tubes and inositolphosphates are separated using ion-exchange resin (Dowex AG1-X8 formateform, 200-400 mesh, BIORAD) columns. Inositol phosphate separation wasdone by first eluting glycero phosphatidyl inositol with 8 ml 30 mMammonium formate. Next, total inositol phosphates is eluted with 8 ml700 mM ammonium formate/100 mM formic acid and collected inscintillation vials. This eluate is then mixed with 8 ml of scintillantand [3H] inositol incorporation is determined by scintillation counting.The dpm counts from the duplicate samples are plotted and IC₅₀determinations are generated using a linear least squares fittingprogram.

Abbreviations

-   -   BSA Bovine Serum Albumin    -   CCD Charge Coupled Device    -   CRC Concentration Response Curve    -   DHPG 3,5-dihydroxyphenylglycine    -   DPM Disintegrations per Minute    -   EDTA Ethylene Diamine Tetraacetic Acid    -   FLIPR Fluorometric Imaging Plate reader    -   GHEK GLAST-containing Human Embrionic Kidney    -   GLAST glutamate/aspartate transporter    -   HEPES 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid        (buffer)    -   IP₃ inositol triphosphate

Generally, the compounds were active in the assay above with IC₅₀ valuesless than 10 000 nM. In one aspect of the invention, the IC₅₀ value isless than 1 μM. In a further aspect of the invention, the IC₅₀ value isless than 100 nM.

Screening for Compounds Active Against TLESR

Adult Labrador retrievers of both genders, trained to stand in a Pavlovsling, are used. Mucosa-to-skin esophagostomies are formed and the dogsare allowed to recover completely before any experiments are done.

Motility Measurement

In brief, after fasting for approximately 17 h with free supply ofwater, a multilumen sleeve/sidehole assembly (Dentsleeve, Adelaide,South Australia) is introduced through the esophagostomy to measuregastric, lower esophageal sphincter (LES) and esophageal pressures. Theassembly is perfused with water using a low-compliance manometricperfusion pump (Dentsleeve, Adelaide, South Australia). An air-perfusedtube is passed in the oral direction to measure swallows, and anantimony electrode monitored pH, 3 cm above the LES. All signals areamplified and acquired on a personal computer at 10 Hz.

When a baseline measurement free from fasting gastric/LES phase IIImotor activity has been obtained, placebo (0.9% NaCl) or test compoundis administered intravenously (i.v., 0.5 ml/kg) in a foreleg vein. Tenmin after i.v. administration, a nutrient meal (10% peptone, 5%D-glucose, 5% Intralipid, pH 3.0) is infused into the stomach throughthe central lumen of the assembly at 100 ml/min to a final volume of 30ml/kg. The infusion of the nutrient meal is followed by air infusion ata rate of 500 ml/min until an intragastric pressure of 10±1 mmHg isobtained. The pressure is then maintained at this level throughout theexperiment using the infusion pump for further air infusion or forventing air from the stomach. The experimental time from start ofnutrient infusion to end of air insufflation is 45 min. The procedurehas been validated as a reliable means of triggering TLESRs.

TLESRs is defined as a decrease in lower esophageal sphincter pressure(with reference to intragastric pressure) at a rate of >1 mmHg/s. Therelaxation should not be preceded by a pharyngeal signal ≦2 s before itsonset in which case the relaxation is classified as swallow-induced. Thepressure difference between the LES and the stomach should be less than2 mmHg, and the duration of the complete relaxation longer than 1 s.

1. A compound of formula I

as well as a pharmaceutically acceptable salt, hydrate, isoform and/orenantiomer thereof.
 2. The compound according to claim 1, wherein thecompound is the S-enantiomer.
 3. The compound according to claim 1,wherein the compound is the R-enantiomer.
 4. The compound according toany one of claims 1-3 in crystalline form.
 5. The hydrochloride salt ofa compound according to claim
 1. 6. The sulphate salt of a compoundaccording to claim
 1. 7. A pharmaceutical composition comprising acompound according to any one of claims 1, 5 or 6 as an activeingredient, together with a pharmacologically and pharmaceuticallyacceptable carrier.
 8. A method for the treatment or prevention of amGluR5 receptor-mediated disorder, wherein an effective amount of acompound according to any one of claims 1, 5 or 6 is administered to asubject in need of such treatment or prevention.
 9. The method accordingto claim 8, wherein said disorder is a neurological disorder.
 10. Themethod according to claim 8, wherein said disorder is a psychiatricdisorder.
 11. A method according to claim 8, wherein said disorder isany one of gastroesophageal reflux disease, IBS, functional dyspepsia,cough, obesity, Alzheimer's disease, senile dementia, AIDS-induceddementia, Parkinson's disease, amyotrophic lateral sclerosis,Huntington's Chorea, migraine, epilepsy, schizophrenia, depression,anxiety, acute anxiety, obsessive compulsive disorder, ophthalmologicaldisorders such as retinopathies, diabetic retinopathies, glaucoma,auditory neuropathic disorders such as tinnitus, chemotherapy inducedneuropathies, post-herpetic neuralgia and trigeminal neuralgia,tolerance, dependency, addiction and craving disorders,neurodevelopmental disorders including Fragile X, autism, mentalretardation, schizophrenia and Down's Syndrome, pain related tomigraine, inflammatory pain, neuropathic pain disorders such as diabeticneuropathies, arthritis and rheumatitiod diseases, low back pain,post-operative pain, pain associated with various conditions includingangina, renal or billiary colic, menstruation, migraine and gout;stroke, head trauma, anoxic and ischemic injuries, hypoglycemia,cardiovascular diseases and epilepsy.
 12. The method according to claim11, wherein said disorder is a chronic pain disorder.
 13. The methodaccording to claim 11, wherein said disorder is an acute pain disorder.14. The method according to claim 11, wherein said disorder is anxiety.15. The method according to claim 11, wherein said disorder isdepression.
 16. The method according to claim 11, wherein said disorderis Parkinson's disease.
 17. The method according to claim 11, whereinsaid pain disorder is a neuropathic pain disorder.
 18. The methodaccording to claim 11, wherein said pain disorder is migraine.
 19. Themethod according to claim 11, wherein said pain disorder is inflammatorypain.
 20. The method according to claim 11, wherein said disorder isgastroesophageal reflux disease.
 21. The method according to claim 11,wherein said disorder is cough.